A variety of sensors are utilized to detect conditions, such as pressure and temperature. The ability to detect pressure and/or temperature is an advantage to any device exposed to variable pressure conditions, which can be severely affected by these conditions. An example of such a device is a catheter, which of course, can experience variations in both temperature and pressure. Many different techniques have been proposed for sensing the pressure and/or temperature in catheters, and for delivering this information to an operator so that he or she is aware of pressure and temperature conditions associated with a catheter and any fluid, such as blood flowing therein.
One type of sensor that has found wide use in pressure and temperature sensing applications is the Surface Acoustic Wave (SAW) sensor, which can be composed of a sense element on a base and pressure transducer sensor diaphragm that is part of the cover. For a SAW sensor to function properly, the sensor diaphragm should generally be located in intimate contact with the sense element at all pressure levels and temperatures.
One of the problems with current SAW sensor designs, particularly those designs adapted to delicate pressure and temperature sensing applications, is the inability of conventional SAW sensing systems to meet the demand in low pressure applications. (e.g., 0 to 500 mmHg), while doing so in an efficient and low cost manner. Such systems are inherently expensive, awkward, and often are not reliable in accurately sensing tire air pressure and temperature. There is a continuing need to lower the cost of SAW sensor designs utilized in pressure and/or temperature sensing applications, particularly wireless pressure sensors.
To lower the cost and raise efficiency, few components, less expensive materials and fewer manufacturing-processing steps are necessary. In order to achieve these goals, it is believed that a disposable pressure sensor diaphragm should be implemented, along with reusable wireless transducers. To date, such components have not been achieved. It is therefore believed that a solution to such problems involves a disposable low cost SAW sensor packaging system, which can be integrated into a catheter and interrogated wirelessly. Such a system is described in greater detail herein.